181.
Match the column I with column II and mark the appropriate choice.
| Column I | Column II | ||
|---|---|---|---|
| a. | $$Li$$ | 1. | Role in biological systems |
| b. | $$K$$ | 2. | Golden yellow flame |
| c. | $$Na$$ | 3. | Photoelectric cell |
| d. | $$Cs$$ | 4. | Carbonate decomposes on heating |
A
a - 4, b -1 , c - 3, d - 2
B
a - 1, b - 3, c - 2, d - 4
C
a - 3, b - 2, c - 1, d - 4
D
a - 4, b - 1, c - 2, d - 3
Answer :
a - 4, b - 1, c - 2, d - 3
182. When sulphur is heated with $$NaOH\left( {aq} \right).$$ The compounds formed are
A
$$N{a_2}S + {H_2}O$$
B
$$N{a_2}S{O_3} + {H_2}O$$
C
$$N{a_2}S + N{a_2}{S_2}{O_3} + {H_2}O$$
D
$$N{a_2}{S_2}{O_3} + {H_2}O$$
Answer :
$$N{a_2}S + N{a_2}{S_2}{O_3} + {H_2}O$$
183. Which of the following is not present in portland cement?
A
$$C{a_3}A{l_2}{O_6}$$
B
$$C{a_3}Si{O_5}$$
C
$$C{a_2}Si{O_4}$$
D
$$C{a_3}{\left( {P{O_4}} \right)_2}$$
Answer :
$$C{a_3}{\left( {P{O_4}} \right)_2}$$
184. Sulphates of $$Be$$ and $$Mg$$ are readily soluble in water but sulphates of $$Ca, Sr$$ and $$Ba$$ are insoluble. This is due to the fact
A
the greater hydration enthalpies of $$B{e^{2 + }}$$ and $$M{g^{2 + }}$$ overcome the lattice enthalpy
B
high lattice enthalpy of $$B{e^{2 + }}$$ and $$M{g^{2 + }}$$ makes them soluble in water
C
solubility decreases from $$BeS{O_4}$$ to $$BaS{O_4}$$ due to increase in ionic size
D
$$BeS{O_4}$$ and $$MgS{O_4}$$ are ionic in nature while other sulphates are covalent
Answer :
the greater hydration enthalpies of $$B{e^{2 + }}$$ and $$M{g^{2 + }}$$ overcome the lattice enthalpy
185.
Match the column I with column II and mark the appropriate choice.
A
A - iv, B - i, C - ii, D - iii
B
A - iv, B - i, C - iii, D - ii
C
A - ii, B - iii, C - iv, D - i
D
A - iii, B - i, C - iv, D - ii
Answer :
A - iii, B - i, C - iv, D - ii
186. The substance not likely to contain $$CaC{O_3}$$ is
A
calcined gypsum
B
sea shells
C
dolomite
D
a marble statue
Answer :
calcined gypsum
187. One mole of magnesium nitride on the reaction with an excess of water gives :
A
two moles of ammonia
B
one mole of nitric acid
C
one mole of ammonia
D
two moles of nitric acid
Answer :
two moles of ammonia
188. When $$BeC{l_2}$$ is hydrolysed, white fumes of gas are given out. The intensity of fumes intensifies when a rod dipped in moist ammonia is brought near the mouth of the test tube. The gas which comes out during hydrolysis is
A
$$C{l_2}$$
B
$$HCl$$
C
$$N{H_4}OH$$
D
$$N{H_4}Cl$$
Answer :
$$HCl$$
189. Which of the following is most stable ?
A
$$N{a_3}N$$
B
$$L{i_3}N$$
C
$${K_3}N$$
D
$$R{b_3}N$$
Answer :
$$L{i_3}N$$
190. The difference of number of water molecules in gypsum and plaster of Paris is
A
$$\frac{5}{1}$$
B
$$2$$
C
$$\frac{1}{2}$$
D
$$1\frac{1}{2}$$
Answer :
$$1\frac{1}{2}$$